Metallurgy of copper.



R. F. BACON.`

METALLURGY 0F COPPER. APPLICATION man MAH.20,1915.

LMLB@ Patented Aug. 24,1915.

ZZJJeJ f m @5U/mond 56600 RAYMOND F. BACON, OF PITTSBURGH, PENNSYLVANIA, ASSIGNOR T0 META-LS RESEARCH COMPANY, OF NEW YORK, N. Y., A CORPORATION OF MAINE.

METALLURGY OF COPPER.

Application filed March 20, 1915.

T0 all/whom t may concern Be it known that I, RAYMOND F. BACON, residing at and whose post-oiice address is Pittsburgh, Allegheny county, State of Pennsylvania, have invented certain new and useful Improvements in vMetallurgy' of Copper; and I do hereby declare the following to be a full, clear, and eXact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

The present invention relates to certain new and useful improvements in the hydrometallurgy of copper and particularly to the recovery of copper from solutions of copper salts, such as are obtained by the liXiviation of copper ores and furnace residues by means of sulfuric acid or hydrochloric acid, or such as are present in mine waters and the like. l

The practice of the invention, in its preferred form, involves a process wherein, first, hydrogen suld is produced by reaction, at av relatively low temperature, between sulfur and a hydrocarbon; secondly, wherein aportion of the hydrogen sulfid reacts with sulfur dioxid to produce a quantity of sulfur equal in amount to that. which is utilized in the iirst step of the operation; thirdly, wherein the remainder of the hydrogen suld produced in the rst step of the operation is employed for the precipitation of copper sulid from the copper salt solution (say a solution of copper sulfate or copper chlorid), and with the simultaneous restoration of sulfuric acid to the solution; and fourthly, wherein the copper sulfid is roasted, the resulting sulfur dioXid fumes Abeing thereupon utilizable in the second step of the process. The solution from which the copper has been precipitated in the form of copper chlorid and which, as the result of the reaction has had its sulfuric acid or hydrochloric acid regenerated therein, may be employed for the liXiviation of a further quantity of ore or the like.

In order to produce a quantity of hydrogen suld adapted to the convenient and eiiicient employment ofthe process, elemental sulfur, as, for instance, precipitated sulfur from a former operation) is treated with a hydrocarbon, as, for instance, what is known as hydrocarbon residue, and at a temperature whichmay conveniently be that of the Specification of Letters Patent.

Patented Aug. 2d, 1915.

serial No. 15,857.

boiling point of the hydrocarbon employed, which, in the case of hydrocarbon residue, would vary from say 300o C. to 360CA C. The temperature employed should not materially exceed the boiling point of the hydrocarbon, for the reason that hydrogen suld begins to dissociate at a temperature of about 4:00,D C. .and such dissociation becomes increasingly important at higher temperatures, so that 1t l1s preferable to restrict the temperature accordingly, not permitting it to rise above say 500o C. ,So`also, it is found preferable to employ a quantity of hydrocarbon not materially exceeding and closely approaching the quantity required to satisfy the contemplated reaction, for the reason that when the amount of hydrocarbon is thus restricted, the coke (which, with the hydrogen suld is the product of the reaction) is found to be harder and denser,

and therefore better adapted for most of the' luses for which coke is intended,-particu larly as a constituent of the charge of a blast furnace or the like, i. e., as metallurgical coke. The reaction involving this simultaneous production of hydrogen sulfid and coke may be expressed by the following general equation:

Another portion of the hydrogen suld produced in the irst step of the operation is then employed to precipitate the copper, in the form of copper sulfid, from the copper salt solution, which latter, as hereinbefore stated, may be obtained from any suitable available source, as, for instance, `by liXiviating copper ores with sulfuric acid or hydrochloric acid, or which may be available as mine waters holding a copper salt in solution. The resulting reaction may be eX- pressed by the following formula:

The resulting spent solution containing the regenerated sulfuric acid or hydrochloric acid, as the case may be, may be einployed for the liXiviation of a further body of ore. The copper sulid resulting Jfrom the third step of the operation is then roasted, With the production of copper oXid, and of sulfur dioXid in the products of combustion, in accordance With the following formula:

(4) CuS -I- lO--epCuO SOZ.

It will novv be evident that the SO2 gases thus produced are available for re-use in the second step of the operation.v Accordingly, the procedure described permits the constant reutilization, in the cycle, of the sulfur. dioxid fumesgiven olf in the roasting operation, and, as hereinbefore pointed out, the elemental sulfur produced in the second step of the operation is utilizable for the production of further quantities of hydrogen sullid; so that the procedure involves a selfsustaining operation in its several steps, in the sense'that the hydrogen sulfid, the sulfur, and the sulfur dioXid produced in the several stages are utilized in subsequent stages thereof. The ultimate products of the operation consist `of copper oXid, and a high grade of coke, and, if desired, the coke may be employed for the reduction of the copper oXid to metallic copper. So also,

as hereinbefore pointed out, the copper solution treated is regenerated and therefore made available for the liXiviation of a further quantity of ore.

In the accompanying drawing are represented, for convenience of reference, in appropriate grouping, the reactions characterizing the practice of the invention.

Having thus described my invention, what I claim is:

The method of carrying on a cyclic operation for the recovery of copper from solutions containing it, which consists first, in producing hydrogen sullid; secondly, producing elemental sulfur by reaction between sulfur dioXid and a portion of .said hydrogen sulfid; thirdly, employing the remaining portion of the hydrogen sulid for precipitating the copper, as copper suld, from the copper salt solution to'be treated While simultaneously yregenerating the solution; fourthly, roasting the copper suliid, With the simultaneous production of sulfur dioXid; the elemental'sulfur and the sulfur dioXid produced in the second and fourth stages, respectively, being subsequently utilized in maintaining a cyclic operation, z'. e., by using said sulfur in a recurrent rst stage, and said sulfur dioXid in a recurrent second stage thereof; substantially as described.

In testimon whereof I afliX my signature, in presence o tvvo Witnesses.

RAYMOND F. BACCN.

Witnesses:

KATHARINE SCHULZ, M. A. BILL. 

